I'm a hot rodder at heart, and understand why you may want to hot rod a 1-ton. But I think you might find it cheaper to get where you want to go if you can swap your way into a 1/2-ton truck.
Your 3800 has a 137 inch wheel base, where a 3/4-ton is 125 and a 1/2-ton is only 116. If you can find a 1/2-ton bed or replace the 1-ton sides with 1/2-ton sides, you can shorten the bed reasonably.
The section height of the 1-ton frame is quite a bit taller than a 1/2-ton, and the exact location of some parts, and the width from under the cab all the way back is different. The steel is also thicker. Together these mean it will weigh a lot more.
Shortening the box and frame, and the weight of the frame are reasons to consider a 1/2-ton instead of this 1-ton.
Okay with those issues out of the way, let me suggest a way to achive what you want, based on the truck you have. And do it for a relatively small investment.
There are no disk brake kits available for your current front axle but you could swap a 1/2-ton front axle under the truck and use a disk kit for one of those. And since you want to lower the truck, about $400 will buy a new dropped axle. That lowers the truck and puts disk brakes on the front. Probably under $1,000 total if you shop carefully. The key is swapping to 1/2-ton stuff.
At the rear install a later rear axle using a $150 axle kit. Start with an axle that has disk brakes and that piece is covered too.
Remove the original motor and transmission, remove the bellhousing crossmember, and purchase and install one of the V-8 crossmembers that are on the market. Those will set you back another $150 or so.
You didn't list power steering, but since modifying the steering column and box location is necessary to fit the V-8 in place you might as well go with one of the power steering kits too.
I've not addressed some of the details, and this approach probably spends a couple thousand before you're done, it was intended to illustrate how you can achive what you describe without making the radical changes you have proposed. Its probably cheaper than the frame swap approaches.
I figure its your truck and you can do with it as you please. But you'll find lots of experience here, and I think you'll want to really understand why people make various suggestions before rejecting any of them.
I'm building a 1-ton hot rod myself, but my purpose is a fun classic trailer puller and I want the beef of the 1-ton. I'm also doing a 1/2-ton hot rod for fun.
